Add custom feeds selector, rework search, simplify onboarding (#325)

* Get home screen's swipable pager working with the drawer

* Add tab bar to pager

* Implement popular & following views on home screen

* Visual tune-up

* Move the feed selector to the footer

* Fix to 'new posts' poll

* Add the view header as a feed item

* Use the native driver on the tabbar indicator to improve perf

* Reduce home polling to the currently active page; also reuse some code

* Add soft reset on tap selected in tab bar

* Remove explicit 'onboarding' flow

* Choose good stuff based on service

* Add foaf-based follow discovery

* Fall back to who to follow

* Fix backgrounds

* Switch to the off-spec goodstuff route

* 1.8

* Fix for dev & staging

* Swap the tab bar items and rename suggested to what's hot

* Go to whats-hot by default if you have no follows

* Implement pager and tabbar for desktop web

* Pin deps to make expo happy

* Add language filtering to goodstuff

src/view/com/posts/FollowingEmptyState.tsx

@@ -0,0 +1,81 @@
+import React from 'react'
+import {StyleSheet, View} from 'react-native'
+import {useNavigation} from '@react-navigation/native'
+import {
+  FontAwesomeIcon,
+  FontAwesomeIconStyle,
+} from '@fortawesome/react-native-fontawesome'
+import {Text} from '../util/text/Text'
+import {Button} from '../util/forms/Button'
+import {MagnifyingGlassIcon} from 'lib/icons'
+import {NavigationProp} from 'lib/routes/types'
+import {usePalette} from 'lib/hooks/usePalette'
+import {s} from 'lib/styles'
+
+export function FollowingEmptyState() {
+  const pal = usePalette('default')
+  const palInverted = usePalette('inverted')
+  const navigation = useNavigation<NavigationProp>()
+
+  const onPressFindAccounts = React.useCallback(() => {
+    navigation.navigate('SearchTab')
+    navigation.popToTop()
+  }, [navigation])
+
+  return (
+    <View style={styles.emptyContainer}>
+      <View style={styles.emptyIconContainer}>
+        <MagnifyingGlassIcon style={[styles.emptyIcon, pal.text]} size={62} />
+      </View>
+      <Text type="xl-medium" style={[s.textCenter, pal.text]}>
+        Your following feed is empty! Find some accounts to follow to fix this.
+      </Text>
+      <Button
+        type="inverted"
+        style={styles.emptyBtn}
+        onPress={onPressFindAccounts}>
+        <Text type="lg-medium" style={palInverted.text}>
+          Find accounts to follow
+        </Text>
+        <FontAwesomeIcon
+          icon="angle-right"
+          style={palInverted.text as FontAwesomeIconStyle}
+          size={14}
+        />
+      </Button>
+    </View>
+  )
+}
+const styles = StyleSheet.create({
+  emptyContainer: {
+    // flex: 1,
+    height: '100%',
+    paddingVertical: 40,
+    paddingHorizontal: 30,
+  },
+  emptyIconContainer: {
+    marginBottom: 16,
+  },
+  emptyIcon: {
+    marginLeft: 'auto',
+    marginRight: 'auto',
+  },
+  emptyBtn: {
+    marginVertical: 20,
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    paddingVertical: 18,
+    paddingHorizontal: 24,
+    borderRadius: 30,
+  },
+
+  feedsTip: {
+    position: 'absolute',
+    left: 22,
+  },
+  feedsTipArrow: {
+    marginLeft: 32,
+    marginTop: 8,
+  },
+})